Semiconductor Memory Voltage Circuit Stabilization
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Solution Overview
Problem
Conventional semiconductor memory systems experience access delays when switching from dummy reading to normal data reading due to fluctuations in internal power source voltage, which is not maintained at a prescribed level during shortened address periods.
Innovation Solution
An internal power source voltage generating circuit that includes a first boosting part and a second boosting part with a condenser and a boost driving control circuit, where the external power source voltage is applied to the condenser to charge it and raise the internal power source voltage if it falls below a threshold, ensuring a stable voltage for normal data reading operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the address period is shortened to improve access speed, then productivity increases, but the internal power source voltage cannot be maintained at the prescribed level, causing reliability to deteriorate
Solution Approach 1:
The condenser is charged in advance during periods when the internal power source voltage is stable, storing electrical energy that can be rapidly discharged to boost the voltage when needed. This preliminary charging action ensures that voltage support is available before the actual need arises, allowing short address periods without voltage instability.
Solution Approach 2:
The condenser acts as an intermediary energy storage element between the voltage boosting circuit and the internal power source. It decouples the timing of voltage generation from voltage consumption, allowing the system to maintain stable voltage during short address periods by discharging stored energy when the address period is too short for normal boosting operation.
2Reliability
If dummy reading is performed to prepare for normal data reading, then access accuracy improves, but the internal power source voltage fluctuates, causing loss of time
Solution Approach 1:
The condenser is charged during the dummy reading period in preparation for the subsequent normal data reading operation. This preliminary charging ensures that when the address period for normal reading is short, the voltage can be maintained without delay, eliminating access time loss while preserving reading accuracy.
Solution Approach 2:
The charged condenser provides a voltage cushion that compensates for insufficient charging time during short address periods. This beforehand preparation ensures that even if the address period is too short for complete voltage restoration, the stored energy in the condenser maintains the voltage at the required level, preventing access delays.
3Temperature
If the external power source voltage is boosted to generate higher internal power source voltage, then the voltage level increases, but the consumption current decreases, causing the voltage to be insufficient during short address periods
Solution Approach 1:
The condenser serves as an intermediary energy buffer that decouples the relationship between consumption current and voltage level. By storing energy when current is available and releasing it when current is insufficient, the condenser maintains voltage levels during short address periods regardless of instantaneous current consumption, allowing the system to operate with lower average current while maintaining high voltage when needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for a stable internal power source voltage to be maintained, reducing access delays when switching from dummy reading to normal data reading by rapidly charging the condenser and adjusting the voltage to meet the prescribed level, even during address periods shorter than the guaranteed minimum.
Implementation Method 1
a condenser (37) wherein one end of which is connected to the output line (Lout), and while a reference low potential (VSS) is applied to the other end of which, the external power source voltage (VCC) is applied to the output line (Lout) so as to perform a charging operation to charge the condenser (37), and if the internal power source voltage (Vbst) is lower than a threshold voltage, the external power source voltage (VCC) is applied to the other end of which, thereby raising a potential of the other end of the condenser (37)
Data Source
AI summary
An internal power source voltage generating circuit of a semiconductor memory and a corresponding method shorten an access delay upon transition of a data reading operation in an address period shorter than a prescribed minimum period to an operation in the prescribed minimum period. While a boosted voltage of an external power source voltage is supplied to the semiconductor memory as the internal power source voltage via an output line connected to one end of a condenser. A reference low potential is applied to the other end of the condenser and the external power source voltage is applied to the output line, thereby charging the condenser. If the internal power source voltage is lower than a threshold voltage, the internal power source voltage on the output line is boosted by applying the external power source voltage to the other end of the condenser.